Transcription of genetic sequences is the initial step in cellular gene expression and the primary site of regulation of gene expression. Although the general features of prokaryotic transcription are understood, the protein factors and biochemical interactions that control RNA chain elongation and termination are still not well defined. In addition, it is now clear that some sets of bacterial genes that play roles in complex differentiation and metabolic processes are coordinately controlled by novel transcriptional factors (sigma factors) and their associated regulatory genes. Our studies focus on the protein factors and biochemical mechanisms that control transcription; two general lines of research are planned. 1. Studies on factors that modulate elongation/termination of transcription include: a) Purification and biochemical and structural characterization of the tau termination factor and cloning of its gene. b) Studies on the structural features of terminators that determine interaction with tau and nusA termination factors. c) Studies of the sequence and factor dependence of the RNA release and enzyme release reactions in termination. d) Studies on the interaction of purified nus gene proteins and other factors with the elongating RNA polymerase. 2. Studies of the Bacillus subtilis Sigma28 gene and overexpression of the Sigma28 protein, b) Biochemical study of the interactions of Sigma28-RNA polymerase (ESigma28) with its promoters (P28), c) Determination of the effect of the spoOA protein on in vitro transcription by ESigma28, d) Disruption of the Sigma28 gene to determine its cellular role, e) Sequencing of additional Sigma28 promoters and their coding sequences, f) alteration of P28 to determine sequences required for recognition and regulation in vitro and in vivo.